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61.
J. Jung H. S. Jeong H. H. Chung M. J. Lee J. H. Jin K. B. Park 《Journal of Radioanalytical and Nuclear Chemistry》2003,255(3):543-546
The radioactive concentrations of radionuclides were measured in the soil and groundwater below the 12 GeV proton beam-line tunnel at KEK. Various long-lived radionuclides, (7Be, 22Na, 46Sc, 54Mn, 60Co, 134Cs, 152Eu and 154Eu) were observed in the soil samples by -ray spectra measurements, and 3H was also detected by liquid scintillation counting. On the other hand, 3H, 22Na and 54Mn, which were leached from the soil were measured in the groundwater below the EP2 beam line. 3H and 22Na were also found in slight amounts in groundwater collected in a well dug beside the East Counter Hall. From a comparison with the radioactive concentration in soil and groundwater, the order of the leaching percentages were 3H>22Na>54Mn. This tendency was in agreement with an experimental result of the RI laboratory. 相似文献
62.
Kyu Ho Chae Kyung Hee Sung 《Journal of polymer science. Part A, Polymer chemistry》2004,42(4):975-984
A polymeric photobase generator containing oxime–urethane groups was prepared by copolymerization of methyl methacrylate and methacryloxyethyl benzophenoneoxime urethane, and its photo and thermal crosslinking reaction after irradiation was examined from the measurement of UV and IR absorption spectral changes, insoluble fraction, and molecular weight changes. The photo‐crosslinking reaction of the copolymer film was more efficient when irradiations were carried out with 310 nm UV light in the presence of benzophenone than with 254 nm UV light without the addition of benzophenone. The crosslinking reaction increased after postexposure baking (PEB), and this thermal crosslinking reaction mechanism was studied from the identification of the photolysis products of a model compound, benzophenoneoxime phenylurethane, by a high‐performance liquid chromatography. The results indicate that the thermal crosslinking reaction of the copolymer after PEB is due to the formation of urea‐type chemical bonds. Resist properties of the copolymer were examined from the measurement of normalized thickness and micropattern development. A negative tone image with a resolution of 2 μm was obtained with this copolymer, having a sensitivity (D) of 1200 mJ/cm2 and contrast (γn) of 1.31, when irradiation was carried out with 310 nm UV light in the presence of benzophenone following chloroform development. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 975–984, 2004 相似文献
63.
As a new type of foldamers, oligoindoles containing 4, 6, and 8 indole rings were synthesized, and their folding properties were characterized by a combination of 1H NMR techniques and UV/visible titration experiments. When chloride was added, the NH signals of the oligoindoles were downfield shifted as a result of hydrogen-bond formation, and the aromatic signals were upfield shifted by stacking between two indoles. Moreover, the ROESY experiment provided definitive NOE evidence for the helical stacking in the presence of chloride. Finally, the UV/visible titration experiments demonstrated that the oligoindoles formed 1:1 complexes with chloride, and the association constants greatly increased with increasing the number of the indole NHs. These observations are all consistent with the fact that oligoindoles adopt a helical conformation when complexed with chloride by hydrogen-bonding interactions. 相似文献
64.
This paper describes an efficient synthetic route for various types of novel carbocyclic nucleosides. The required stereochemistry of the targeted nucleosides was successfully obtained with use of Grubbs cyclization and Trost allylic alkylation from the carbohydrate chiral template "D-lactose". 相似文献
65.
Lee JS Zhang MH Yun EK Geum D Kim K Kim TH Lim YS Seo JS 《Experimental & molecular medicine》2005,37(5):427-435
Vimentin is an intermediate filament that regulates cell attachment and subcellular organization. In this study, vimentin filaments were morphologically altered, and its soluble subunits were rapidly reduced via cadmium chloride treatment. Cadmium chloride stimulated three major mitogen-activated protein kinases (MAPKs): extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38, and led apoptotic pathway via caspase-9 and caspase-3 activations. In order to determine whether MAPKs were involved in this cadmium-induced soluble vimentin disappearance, we applied MAPK-specific inhibitors (PD98059, SP600125, SB203580). These inhibitors did not abolish the cadmium-induced soluble vimentin disappearance. Caspase and proteosome degradation pathway were also not involved in soluble vimentin disappearance. When we observed vimentin levels in soluble and insoluble fractions, soluble vimentin subunits shifted to an insoluble fraction. As we discovered that heat-shock protein 27 (HSP27) was colocalized and physically associated with vimentin in unstressed cells, the roles of HSP27 with regard to vimentin were assessed. HSP27-overexpressing cells prevented morphological alterations of the vimentin filaments, as well as reductions of soluble vimentin, in the cadmium-treated cells. Moreover, HSP27 antisense oligonucleotide augmented these cadmium-induced changes in vimentin. These findings indicate that HSP27 prevents disruption of the vimentin intermediate filament networks and soluble vimentin disappearance, by virtue of its physical interaction with vimentin in cadmium-treated SK-N-SH cells. 相似文献
66.
Moonhor Ree Jong-Seong KimJae Jung Kim Byeang Hyean KimJuyoung Yoon Heesoo Kim 《Tetrahedron letters》2003,44(45):8211-8215
The synthesis of novel cavitands containing four fluorophores [tert-butoxycarbonyl protected 2,2′-bis(furyl)benzidine (t-BOC FurylBz) or 5,5′-bis(4-aminophenyl)-2,2′-bifuryl (t-BOC PFDA)] and ionophoric functional groups on the upper rim is reported. The cavitands bearing the four fluorophores emit blue light photoluminescence. In particular, the cavitand containing PFDA moieties exhibits a high photoluminescence quantum yield. 相似文献
67.
Jin R Jureller JE Kim HY Scherer NF 《Journal of the American Chemical Society》2005,127(36):12482-12483
Femtosecond laser excited second harmonic (SH) activity from single Ag nanoparticles is reported. A correlation of SH single-particle measurements with high-resolution imaging of particle morphology by TEM was achieved by creating position markers on an optical and electron transparent substrate (Si3N4 thin film, approximately 100 nm). We compared the SH activity of single Ag nanoparticles (nanospheres versus nanorods) and cluster structures (composed of two or multiple particles, e.g., dimers and trimers). The direct correlation of single-particle structures and SH activity, spectral and power dependence, strongly suggests one-photon resonant driven nonlinear oscillator response mechanism. 相似文献
68.
Somatostatin (SST) is a well-known neuropeptide that is expressed throughout the brain. In the cortex, SST is expressed in a subset of GABAergic neurons and is known as a protein marker of inhibitory interneurons. Recent studies have identified the key functions of SST in modulating cortical circuits in the brain and cognitive function. Furthermore, reduced expression of SST is a hallmark of various neurological disorders, including Alzheimer’s disease and depression. In this review, we summarize the current knowledge on SST expression and function in the brain. In particular, we describe the physiological roles of SST-positive interneurons in the cortex. We further describe the causal relationship between pathophysiological changes in SST function and various neurological disorders, such as Alzheimer’s disease. Finally, we discuss potential treatments and possibility of novel drug developments for neurological disorders based on the current knowledge on the function of SST and SST analogs in the brain derived from experimental and clinical studies.Subject terms: Molecular neuroscience, Drug development 相似文献
69.
Chan Sik Cho Tae Kyung Kim Tae‐Jeong Kim Sang Chul Shim Nam Sik Yoon 《Journal of heterocyclic chemistry》2002,39(2):291-294
Nitroarenes are reductively cyclized with 3‐amino‐1‐propanols in dioxane/H2O in the presence of a ruthenium catalyst and tin(II) chloride dihydrate together with isopropanol to afford the corresponding quinolines. A reaction pathway involving initial reduction of nitroarenes to anilines, propanol group transfer from 3‐amino‐1‐propanols to anilines, N‐alkylation of anilines by 3‐anilino‐1‐propanols and heteroannulation of 1,3‐dianilinopropanes is proposed. 相似文献
70.
Gwi-Taek Jeong Donn-Hee Park Gwang-Yeon Lee Jin-Myeong Cha 《Applied biochemistry and biotechnology》2006,132(1-3):1077-1088
Biofiltration is a biological process which is considered to be one of the more successful examples of biotechnological applications to environmental engineering, and is most commonly used in the removal of odoriferous compounds. In this study, we have attempted to assess the efficiency with which both single and complex odoriferous compounds could be removed, using one- or two-stage biofiltration systems. The tested single odor gases, limonene, α-pinene, and iso-butyl alcohol, were separately evaluated in the biofilters. Both limonene and α-pinene were removed by 90% or more EC (elimination capacity), 364 g/m3/h and 321 g/m3/h, respectively, at an input concentration of 50 ppm and a retention time of 30 s. The iso-butyl alcohol was maintained with an effective removal yield of more than 90% (EC 375 g/m3/h) at an input concentration of 100 ppm. The complex gas removal scheme was applied with a 200 ppm inlet concentration of ethanol, 70 ppm of acetaldehyde, and 70 ppm of toluene with residence time of 45 s in a one- or two-stage biofiltration system. The removal yield of toluene was determined to be lower than that of the other gases in the one-stage biofilter. Otherwise, the complex gases were sufficiently eliminated by the two-stage biofiltration system. 相似文献